Key to the species of Inocybe in California

A key to the species of Inocybe found in California is presented, based on a recent systematic study of the genus in southern California. The occurrence of nearly 60 species is indicated for the state, augmenting the 16 nominal species previously reported in the literature. Several species with type localities in California or the west coast of the U.S. were re-collected and determined for the first time since their original description. Distinct Inocybe floras appear in northern and southern California, associated with different forests, mixed conifer vs. live oak, respectively. Less than a quarter of the total species occur in both regions. A checklist is provided of nominal Inocybe species of California, based on published reports and herbaria records at SFSU and LAM.